Thermostat for centrally-heated plants.



No. 865,862. PATENTED SEPT. l0, 1907.

' R. BRUKENHAUS.

THERMOSTAT FOR GENTRALLY HEATED PLANTS.

APPLIOATION FILED JAN. 2z, 1904.

-52/I ii n PATENT' OFFICE.

ROBERT BRUKENHAUS, oF HAsPE, NEARHAGEN, GERMANY.

, THERMOSTAT FOR CENTRALLY-I-IATD PLANTS.

Specification' of Letters Patent.

Alatented Sept. 10, 1907.

Application led January 22, 1904. Serial No. 190,153.

To all whom it may concern:

Be it known that I, RORERT BRUKENHAUS, `a subv ject of the King of Prussia, residing in Haspe, near Hagen, in the Province of. Westphalia, German Empirc, have invented certain new and useful Improvements in Thermostats for Centrally-Heated Plants, of which the following is a full, clear, and exact specifi'- cation.

This invention rela'tes to thermostats, especially adapted for use in centrally heated plants, stationary steam-boilers or the like.

The peculiarityof the new thermostat consists in the arrangement of a compensating tube which is temporarily passed by the heating'medium and closes the main valve or cock at the very moment, when the highest predetermined temperature in the room in question is obtained by means of the movement of the expansion tube or pipe, caused by-its lengtheningA through the heat. When the temperature in the respective room is lowered, nntilla certain minimum is reached, the

expansion tube is4 again cooled and by its shortenin the steam cock is opened again.

The invention is shown in the annexed drawing forming a part of this specilicatiomthe improvement illustrated in the figure being preferably employed in cases where heating by low pressure steam is preferred.

The compensating tube a, filled with naphtha or the like` is inclosed in its lower part by a casing b, forming 310 a steam shell; the casing b' being in communication with the small pipe c of the condensation-conduit. A spiral spring w is provided between the upper end a/ of the pipe a and the upper part of the casing b. The l steam cock e is inserted into the steam conduit d, serving for the introduction of steam into the heating bodies.

The said steam cock is rigidly' connected with the compensating tube by means of the lever f and the rod g and normally kept in its original position by means of a counter-weight h. The casing b is connected with the 40 valve chest c by means of a small pipe i, being in communication with the main steam conduit d by the pipe l. The slide valve m of the valve chest is provided wire-conductors, s, s2, s3 with the maximum and minimum thermometer t, and finally with the galvanc battery u, 1M. At the points al, v, fr? of the thermometer platina wires are embedded.

The thermometer t consists of a U-shaped tube of glass the ends oi which are enlarged. The leg having the platinum wire v2 is the maximum leg, the other leg having the platinum wire 'u beingthe minimum leg. The tube contains mercury, the platinum wires 'v and v2 being above the surface or level of the mercury. At the upper part oi the maximum leg over the surface of the mercury is atmospheric air and in the minimum leg of the tube is spirit of wine or alcohol. The pressure of the alcohol is such that thesurface or level of the mercury in the maximum leg stands higher than the surface ofthe mercury in the minimum leg. When the `temperature rises to a certain degree the alcohol expands and presses on the mercury forcing it out of the minimum leg and causing it to rise in the maximum leg and come in contact with the platinum wire o2. When the temperature falls the pressure of the alcohol is reduced and the mercury rises in the4 minimum leg, owing to the weight of the mercury in the maximum leg, and contacts with the platinum wire t.

' The function of the thermostat is as follows: Should the mercury column of the thermometer rise to the point nl' the circuit will be closed and the current will How from the cells u u through the conductor s2 and `contacts rf, q, r2 and further through the electro magnet v K p, conductor s, contact t?, mercury column, contact i 1;/ and conductor s3, back to the cell u. The circuit is 80 therefore closed, so that the electromagnet is energized and moves the armature to the right hand side. Herei by the current is immediately interrupted again, as the tongue q is no longer in contact with 1"; the tongues r and 1" being now in electrical connection with each other. By the before-mentioned action of the electromagnet p/,the slide valve m of the valve chest lc has been likewise brought to the right hand side. Therefore steam is admitted to enter through the channel of the slide valve m and the pipe i into the casing b. By the entering steam the compensating pipe a is heated and the free end a/ of it is moved upwardly, whereby the steam cock is closed. The further supplying of the heating bodies with steam is therefore interrupted and the temperature in the respective room can go no higher, but will soon be lowered by the outer atmosphericjnfluences. When the temperature is lowered so far, that the column oi mercury touches the point '1), the current will flow through the conductor s2, the elec-v tromagnet p, and the conductor s, whereby the arma- 100 ture is moved to the leit hand side. The valve is theref by brought into its original position and the steam supply to thepipe a is again interrupted. The compensating pipea is then cooled and brought into-its normal position opening the steam cock again.

Having now described my said invention, I declare what I claim is:

1. In a thermostatic apparatus, in combination, a steam p'ipe, a steam chamber having an outlet, a bent compensation pipe the one end of which enters the chamber, a vulve controlling the steam pipe connected with the other end of 4 the compensation pipe, a branch conducting steam to the chamber, a valve controlling said branch, a maximum and minimum thermometer having electric contacts, and electro magnetic apparatus controlled by the thermometer and actuating the brancli'valve, substantially as described.V

2. In a thermostatic apparatus, in combination, a steam pipe, a steam chamber having an outlet, a bent compensation pipe, the one end ot which enters the chamber, a valve controlling the steam pipe connected with the other end of the compensation pipe, a branch conducting steam to the chamber, a valve controlling the said branch, a maximum and minimum thermometer having electric contacts. electromagnets one pole of each 'of which is connected respectively with the maximum and minlmum thermometercontacts, a source ot electricity connected to the third thermometer-contact.1an armature for the electromagnets carrying' a double contact and connected with the said ,branch valve, and a triple contact over which the double.

-30th day of December 1903, in the presence of two`subscribint: witnesses. I

ROBERT BRUKENIIAUS.

Witnesses O'r'ro KNIG, J. A. RITTERSHAUS. 

